外文翻譯--球墨鑄鐵的無(wú)損傷檢測(cè)(存儲(chǔ)版)
【正文】 instruction is not prepared the indications shall be evaluated according to the acceptance levels for zone 1 (table 1) and figure A (table 2) and shall be forwarded to the quality department of CUSTOMER for evaluation. Classification of zones The item must be examined according to the zone classification for the actual material cross section thickness (see table 2). For a thickness of the actual material cross section equal to or less than 80 mm examination shall be carried out according to figure A in table 2. For a thickness of the actual material cross section greater than 80 mm examination shall be carried out according to figure B in table 2. (. 100 mm thickness in actual material cross section: 40 mm in depth of the material nearest to the scanning surface from all sides shall be examined according to zone 1, whereas the remaining 20 mm of the centre core shall be examined according to zone 2). Evaluation of indications Indications shall be evaluated according to their type, propagation and zone placement. The acceptance criterias distinguish between the following types of ultrasonic indications: ? Reduction or total loss of back wall echo in areas with parallel surfaces. Indications with simultaneous reduction or total loss of back wall echo. ? Indications in areas without the possibility of a back wall reflection. The mentioned types of indications can appear with or without measurable area. For indications in zone 1 in areas with parallel surfaces, the registration level distinguishes between indications with simultaneous reduction of back wall echo or with simultaneous total loss of back wall echo. In areas without parallel surfaces or when using angle beam probes, all indications are evaluated after the rules for simultaneous total loss of back wall echo. Reduction of back wall echo are indications which are detected only as a reduction of the back wall echo exceeding the recording level for the actual material thickness according to table 1. Propagation (projection on scanning surface) for such indications shall be evaluated in accordance with table 1, zone 1. The indication limits are where the back wall echo is reduced to the actual recording level for the material thickness. Total loss of back wall echo is defined as a reduction greater than the recording level + 6 dB for the actual material thickness. Indications without area are single indications detected by – 1) a reflection greater than the recording level (DSR/KSR) for the actual zone and material thickness, and 2) which do not show any measurable projected area on the scanning surface. Such indications shall be evaluated directly according to table 1, and only the size expressed as DSR shall be recorded. Indications with area are indications detected by – 1) a reflection greater than the recording level (DSR) for the actual zone and material thickness and – 2) which do show a measurable projected area on the scanning surface. The projected area is measured using the 6 dB drop method below the actual recording level. Reflectors in zone 1 as well as indications detected only as a reduction or total loss of the back wall echo shall be evaluated according to table 1, zone 1, and both area and echo amplitude (DRS) shall be recorded.
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